Rudy Giuliani has made a strategic choice in the Republican primary contest. He will stay pro-choice on the issue of abortion, and thus avoid the flip-flopper label that has so harmed former Massachusetts Gov. Mitt Romney.

But Giuliani has a flip-flop in his past. When he first began running for New York City mayor in 1989, he said that he personally opposed abortion, favored overturning Roe v. Wade and opposed public financing of abortions. During that campaign he morphed into an unmodulated pro-choicer. He dropped talk of opposing Roe v. Wade and endorsed taxpayer funding of abortion. By the time he was mayor, he was declaring a "Planned Parenthood Day" in New York and all but pledging to perform abortions himself, should it ever come to that.

Now that's he's running for president he says that he "hates" abortion — something he didn't mention when he gave opening remarks at NARAL's "Champions of Choice" lunch in April 2001. (Back then, New Yorkers had a "distinguished tradition" of promoting abortion.) He now supports a partial-birth ban, which he had opposed. His aides say he supports — or wouldn't seek to change — the Hyde amendment banning Medicaid financing of most abortions, even though he once opposed it.

And these peregrinations are from the candidate who prides himself on fearless straight-talk. None of this is by way of dumping particularly on Giuliani, but to illustrate the governing principle of abortion politics in America: Almost no major politician really cares about it.

What are the odds that every Democratic politician with presidential hopes who once expressed pro-life sentiments — Jesse Jackson, Dick Gephardt, Al Gore, even the fringe candidate Dennis Kucinich — would have epiphanies on abortion that would send them all in the pro-choice direction? Or that both George Bushes would become more pro-life as it happened to suit their ambitions?

It is a little like the athletes who earnestly insist they've always wanted to play for a given team in a given city — but that team almost always happens to be the one that offered the most money.

Romney is the starkest example. He's had double epiphanies, each of which happened to accord with his political interests. One would think Romney, a faithful Mormon, would tend to be pro-life. But when he ran for the Senate in Massachusetts in 1994, he said abortion should be "safe and legal" because the effect that the death of a brother-in-law's sister from an illegal abortion had had on him. Later, when he was a governor gearing up for a presidential bid, the impact of a briefing on the issue of stem-cell research shocked him back into being pro-life.

The first epiphany surely wouldn't have had the same effect if he had been running for the Senate anywhere else besides liberal Massachusetts. And that briefing wouldn't have packed the same punch had he not been thinking about the national stage. Jonathan Last of the Weekly Standard compares becoming pro-life on the stem-cell issue to "an atheist being brought to Christianity on the strength of Intelligent Design theory." With Iowa and New Hampshire looming, Romney is now, finally, epiphany-proof.

Converts on abortion can become genuine. Ronald Reagan signed an abortion-liberalization bill as Governor of California, but became such a committed pro-lifer that he wrote a book on the issue when he was president. Giuliani appeared — prior to his presidential run — to have become a deep-felt evangelist for the pro-choice cause. More important than genuineness, however, is follow-through. The first George Bush's conversion on abortion might have been political, but he acted as a steadfast pro-lifer throughout his presidency.

Politicians aren't like you and me. Most of them consider (to the extent they must — they'd prefer not to think about it) one of the most profound moral issues of the day and see primarily a potential obstacle or boon to their ambitions. That's just a fact of life. Sincerity would be nice, but on abortion, it often has to be optional.